Convertation from XML to JSON is possible automatically on Corezoid side. For this, it is enough to select appropriate XML (text/xml ; application/xml; application/soap+xml) from Content-type and put your XML in CodeEditor of API CALL node

Or you can convert XML to JSON for Corezoid by yourself using freeformatter sevice. You need only to replace value in #text property name: field with #text by #value